<!DOCTYPE html>  
<html lang="en">  
<head>  
    <meta charset="UTF-8">  
    <meta name="viewport" content="width=device-width, initial-scale=1.0">  
    <title>Simple Calculator</title>  
</head>  
<body>  
    <div>  
        <input type="number" id="num1" placeholder="Number 1">  
        <select id="operator">  
            <option value="add">+</option>  
            <option value="subtract">-</option>  
            <option value="multiply">*</option>  
            <option value="divide">/</option>  
        </select>  
        <input type="number" id="num2" placeholder="Number 2">  
        <button onclick="calculate()">Calculate</button>  
    </div>  
  
    <script src="5.js"></script>  
</body>  
</html>